12-10
CONTROL SYSTEM
SM YBD018 1-A.1 GB
x
Case 1: OCT<–DST AND TLD > DI
x
Case 2: OCT<-4 AND TLD>
100
minutes
x
Case 3: OCT is Invalid AND TLD > DI
x
Case 4: Unit is just switched to STBY AND OCT<-DST
x
Case 5: compressor is stopped during heating operation, OCT<-DST AND TLD>DI,
OCT – Outdoor Coil Temperature
OAT – Outdoor Air Temperature
TLD – Time from Last Deicing
DI – Deicing Interval (Time Interval Between Two Deicing)
DT- Deicing Time
DST is defined as:
When OAT>0 or OAT is invalid; then DST=8
When OAT
0; then DST= round down (-
DeicerCoef
* OAT) + 8
Deicing interval time when compressor is first started in heat mode is 30 minutes.
Deicing interval time is changed (increased/ decreased in 10 minutes steps) as a function of deicing
time. If deicing time is shorter than former deicing time, the deicing interval time will be increased. If
deicing time is longer than former deicing time, the deicing interval time will be decreased.
12.7.1.1 Deicing Protection Procedure
COMP
RV
OFAN
EEV
ON
HEAT
COOL
ON
OFF
EEVDeicerOpen
Any
T1
T2
T3
T3
T1
12
0
Threshold
max. 12 minutes
DT
OCT
T1 =
DEICT1
seconds, T2 =
DEICT2
seconds, T3 =
DEICT3
seconds